nonresident training course - Historic Naval Ships Association

The overall requirement of any tactical display system is to provide a visual
display of the real-time deployment of ships and aircraft, the tactical situation, and
the geographical area of the situation.
To perform this requirement, the display system must be able to accomplish
several functions. These system functions include:
Sensor data distribution and display
Tactical data distribution and display
Data display group simulation and testing
The Naval Tactical Data System (NTDS) has evolved into the Combat Direction
System (CDS). Through this evolution, the function and design of the tactical
display system has remained fairly constant. On ships with the AN/UYA-4(V)
display group, the basic equipment and signal flow are as shown in figure 3-1.
The block diagram can be split into three functions: sensor data, tactical data, and
simulated data. Each of these functions ties together at the display console. In the
this chapter, we look at each function and how it affects the picture on the display
console.
SENSOR DATA DISTRIBUTION AND
DISPLAY
Sensor data originates with the ship’s sensors
(radar, sonar, and IFF) and is ultimately displayed as
sweep and video on the display console as shown in
figure 3-1. Sensor data normally consists of two types
of data: antenna position and video signals.
Antenna position data as it originates from the
ship’s sensors must be converted to a form usable by
the AN/UYA-4(V) display consoles. Conversion of
the sensor antenna position data is accomplished by
radar azimuth converters (RACs) or sonar azimuth
converters (SACS). In this chapter, we only discuss
the operation of a RAC. One converter is required for
each of the ship’s sensors. The RAC outputs the
timing signals and X/Y quantities necessary to
generate that radar sweep display. The sweep data is
fed from the RAC to the radar data distribution
switchboard (RDDS) for distribution to the consoles.
generation logic of the consoles and timing signals
from the RAC ensure that the intensified video is
displayed at the proper range on the plan position
indicator (PPI) sweep.
RADAR AZIMUTH CONVERTER (RAC)
The radar azimuth converter, or RAC, converts
position data from each of the ship’s radars into a
digital quantity usable by the display console and the
computer. The antenna position data coming into the
RAC maybe in synchro or digital form, depending on
the characteristics of the radars installed on the ship.
The RAC develops a series of signals known as ∆Υ
and ∆Υ pulse trains and the sign of ∆Χ and sign of
∆Υ to send to the display console to paint the sweep
in the proper position. The RAC also develops a
digital data word that contains the azimuth of the
antenna that is transferred to the CDS computer. This
data word is known as digital theta and is represented
by the Greek letter theta (θ).
Video signals are fed from the sensor or sensors
to the RDDS and then to the consoles. The sweep
3-2